This invention relates to a semiconductor memory device having tunnel diodes.
Two types of random-access memories (RAMs) are known, i.e., a dynamic RAM and a static RAM. A dynamic RAM has a plurality of memory cells each formed of one MOS transistor and one capacitor. A static RAM has a plurality of memory cells each formed of six MOS transistors or four MOS transistors and two resistors. The dynamic RAM needs to undergo a data refreshing operation in order to preserve the data stored therein. The static RAM cannot be made with a high packing density because each of its memory cells includes many elements.